Centerless grinder



June 21, 1932. w, H, CHAPMAN 1,863,832

CENTERLESS GRINDER Original Filed Feb. 12. 1926' 4 Sheets-Sheet l June 21, 1932.

w. H. CHAPMAN 1,863,832

cENTERLl-:ss GRINDER Original Filed Feb. 12, 1926 4 Sheets-Sheet 2 W2k/'am ff., Chapman,

Ey $44 0 @me `une 2 1, 1932.

W. H. GHAPMA'N cENTERLEss GRINDER original Filed Feb, 12, 1926 4 Sheets-sheet 3 W'la'amj. Chapman;

June 21, 1932.- 'w. CHAPMAN 1,863,832

cENTERLEss GRINDER Original Filed Febf l2, 1926 4 Sheets-Sheet 4 Patented June 21, 1932 UNITED STATES PATENT oFFics WILLIAM I-I. CHAPMAN, OF MONTCLAIR, NEW JERSEY, ASSIGNOR T GENERAL M0- TORS CORPORATION, 0F DETROIT, MICHIGAN, A CORPGRATION' OF DELAWARE CENTERLESS GRINDER Original application filed February 12, 1926, Serial No. 87,940. Divided and this application led February 19, 1929. Serial No. 341,112.

rlhis invention relates to centerless grind,- ng and comprises all the novel subject matter herein disclosed. An object of the invention is to provide improved mechanism and steps for setting up centerless grinding machines preparatory to grinding a workpiece to a given size. Another object is to provide mechanism for definitely establishing an unvarying reference axis on the machine so as to locate the work guiding means and slow wheel in positions to tit the work at its desired finished diameter and to produce the same path of travel for work oit any selected diameter.

To these endsand to improve generally upon machines of the character indicated, the invention also consists in the various matters hereinafter disclosed and claimed.

The invention, in its broader aspects, is not necessarily limited to the particular embodiment selected for illustration in the accompanying drawings in which Figure 1 is a plan view with some parts in section, the work guides being removed and the set-up mechanism being in operative position.

Figure 2 is a front elevation with some parts broken away. Y

Figure 3 is aside elevation ofthe work guides and associated mechanism partly broken away and in section.

Figures 4 and 5 are detail sectional views oi' the work guides.

Figure 6 is an end View of the slow head and its carriage.

Figure 7 is a front View of the slow wheel head.

Figures 8 and 9 are central sections, taken at right angles to one another, of the carriage for the slow wheel head.

Figures 1() and 11 are diagrammatic views indicating a work piece being guided up to the wheels and passing between them, and Figure 12 is a plan view.

The numeral 8 indicates a hollow base frame supporting a pan or casting 10`having ways or tracks 12 for a slidable carriage 14 wheel which supports a head 16 for an abradi'ng wheel 18. The wheel 18 is the fast wheel having its hub 20 secured in any suitable way, as

by the clamp plate 22, to the ltapered end of a shaft 24 which rotates on a normally fixed axis in sets of angular contact ballbearings 26 and 28 in the head 16. One set 28 of bearings has its race rings clamped to the shaft and in the head. The other set 26 has its outer race rings slidable in the head and pressed in one direction by springs `30 to prevent play and wear. The-shaft 24 has a pulley 32 driven at high speed by a belt 34 fast wheel, there is provided a truing` tool which is movable parallel to the wheel axis opposite to the line of travel` of a work piece. This comprises dovetail ways 36 for a carriage 38 slidable by means of a screw 40 and a hand wheel 42. On the carriage is adjust- 771",

ably secured a threaded shaft or pin 44 having a diamond 46 projecting through a slot in a wheel guard 48 to engage the wheel.

On the other side of the pan are ways 50 -i'or a carriage 52 which adjustably supports a rockable or tiltable head 54 for a wheel 56. The wheel 56 is the slow or control wheel and it is considerably wider than the fast wheel vand projects more towards the work receiving side of the machine so that the work will first engage the slow wheel against which it is held while passing to the :tast wheel.

`Wheel 56 has a hub 58V clamped to a shaft 62 by a clamp plate 60, the hub being hollow to embrace a portion of the rockable head 54. Shaft 62 is rotatably supported in sets of angular contact ball bearings 64 and 66 in the rockable head, the outer race krings of the set 66 being constantly pressed in one direction to prevent play and wear by springs 68 interposedbetween a iia'nge in the head and a ring 70 which alouts against one of the outer race rings.

For driving the wheel 56 in the same direction as the kwheel 18 and at slower speed, a bevel geary 72 on the wheel shaft meshes with a bevel pinion 74 on a shaft 7 6 mounted Y near one end on ball and roller bearings in a sleeve 7 8 projecting from the rockable head and mounted near the other end on roller bearings 80 in a lateral extension 82 on an Y arm 84 of the rockable head. A gear 86 on shaft 76 meshes with a gear 88 attached to a pulley 90 driven by a belt 92 and rotatably mounted on a stud shaft 94 fastened in the lateral extension 82. rEhe head 54 is tiltably adjustable in curved ways around an axis passing through the center of the slow wheel and through the work contacting portion of the fast wheel to vary the speed of work feed. This aXis is also in line with the axis of the driving pulley 90 so thatfthe driving gearing will act equally well in whatever tilted position the slow wheel is placed. kAs shown in Figures 6 to 9 there are curved ways 96 on the underside of the Vrockable head engaging corresponding tracks or ways 98 in the supporting carriage 52, both sets of ways being curved about the described axis as a center. Adjustment of the head and bracing or support of the overhung parts is effected by a turnbuckle 100 having its right and left threaded portions pivotally connected to a plate 102 on the carriage 52 and to a plate 104 which is fastened to the end cap 106 carrying the ball bearings 66. The sides of the rockable head have lateral extensions 108 engaged by locking eccentrics 110 carried on hand operated shafts 112 jonrnalled in lugs 114 on one end of the carriage 52 and in a single lug 116 near the other end of the carriage. The Vhead can be tilted in either direction from the horizontal so as to i be capable of feeding work through themachine in either direction but preferably thel work enters at the end shown in Figure 2 andthe near end lof the slow wheel shaft is tilted upwardly.

When the slow wheel of a centerless grinder is tilted or skewed, proper feed and grinding of straight cylindrical work-pieces be-. .tween the wheels parallel to the fast wheel axis requires that the wheel be slightly concave. To produce the proper shape of wheel initially is a matter of some difliculty and requires a considerable calculation. According to the present inventiomthe proper shape is produced by a truing 4tool which is mounted to slide across the slow wheel always in 4a line parallel to and on a level with the center of the work path or parallel to the vopposing line contact of thefastlwheel. No

inattei what tilted position the head assumes, the tool generates a curved surface producinga line contact for the work piece. As shown, the carriage 52 has a bracket 117 with ways 118 for aislidable carriage 120 movable by a screw 122 actuated by a hand wheel 124. In standards 126 inthe carriage 120 is adjustably mounted a threaded shaft 128 having a knurled operatingcollar 130 and a clamping screw 132. At the endof the shaft 128 isa diamond 134 which is on a level with the aXisabout which the head tilts to project through a slot in a wheelguard 136 to renvaxis at the saine level. Y

For use in setting up the Vwork engaging instrumentalities to produce a given diainy eter of work and for preserving an unvarying reference axis by which these instrumen- -talities can be so located that all sizes of work will travel the same path, the following mechanism is provided. Secured -to the pan at front and rear are pairs of standards 140 between which a centering `rod or arbor 142 can be temporarily supported on taper centers 144 mounted on arms 146each of which is pivoted at 148 to astandard 140. The

front taper center is adjustable by a hand screw to aid l in placing the centering rod in the true reference aXis of the machine on a level with the wheel centers. The ends of the arms 146 have hand screws 150 arranged to enter tapped openings in the standards to lock the arms in horizontal position when the centering mechanism is in use or to lock the arms in vertical position when the cen- A tering rod iis-removed. The tappedopenings 152 for holding the arms in vertical position are on the vsame standards as the pivots 148 and the others are on the other standards on a level with the pivots. In use, a sleeve S-of the same size as the finished work desired is sleeved on the centering rod 142 and then the wheels are individually fed into working relation tothis reference wort-piece which then lies between the wheels attheir point of nearest approach. The work supports and guides Vwhich will'now be described are also moved to work engaging and guiding position and then the centering rod and its r v The standards have opposed ways 154 for Y Areference work-piece are removed.

upper and lower pairs of vertically slidable blocks 156which are split at the ends so that they can be secured in adjusted position by clamping bolts 158. The lower blocks carry alower bar or Work guide V160 Vand the upper blocks carry an upper bar or work guide 162, both guides being movable in unison Vtowards o r -from eachother. To the lower bar are clamped front andrear pairs of guide plates or jaws 164 which are inclined to engage and guide the sides of work pieces as indicated in Figure 10. The vertical webs ofthe plates are slotted as at 166 to receive clamping` bolts 168 by which the plates may beset tovcontact vwith work-,pieces of different diameters.

the work-pieces also resting on 'the guide bars sothat'a three point contact isprovided The Y pairs of plates or jaws 164` guide vthe work :up tothe wheels and away from the wheels.

Opposite the :slow wheel, the lower jguide bar has va recess 1.70 for a vertical blade172 having its Aupper yend bevelled fasat .1f7 4 .to Vproject `a little above :the bar and above a hardened wear plate 176 which may be detachably secured to the bar. The blade has slots for clamping screws 178 and is vertically adjustable by screw `bolts 180 threaded in the'bar and abutting against the low- 10 er end of the blade. The upper bar has a recess 182 'for an upper blade 184 which has its lower end bevelled, as at 186, to project below the upper bar and its wear plate 188.

This blade is yieldable-upwardly against the tension `of a leaf spring 190 interposed `between the lupper edge of the blade and the top of the recess. Downward movement of the blade is limited by adj ustablestop screws 192 threaded in the blade and passing loosely through openings in the bar. The blade is .guided by a cover plate 194 abutting a ledge 195 in the recess and held against the ledge by bolts 196 having flats onV their heads so that the blade can be removed lon a partial turn of the bolts. The bevelled blades tend to hold the work .pieces against the slow wheel so that rotation is imparted to the work before the work reaches the fast wheel :and

.hence the likelihood ofgrinding a flat-on the ,30 work orithe likelihood of the end of the work vpiece hitting the side of the wheel is'eliminated. The upper guide bar 162 normally has a very slight clearance with work-pieces but prevents them from rising or tilting.

The work guiding bars and their slide blocks are movable towards or from each other simultaneously by the following mechanism. The'lower slide blocks 156 are carried by rotatable j ack screws 198 guided V40 loosely in the base of the standards and supported and fed endwise by worm wheels 200 which are connected for simultaneous rotation by a shaft 202. The upper slide blocks 156 are suspended by rotatable screws 204 guided loosely through. cross bars 205 connecting the standards and supported and fed endwise by worm wheels 206 which are connected for simultaneous rotation by a shaft 208. The worm wheels 200 and 206 at the front are driven by worms 210 and 212 respectively and the worm shafts are connected by sprocket wheels 214 and a sprocket chain 216, the upper worm shaft being controlled by a hand wheel 218. The above described l mechanism will cause the upper and lower guide bars to approach or recede from one another in equal degree so that work pieces of different diameters will be supported on a level with the wheels. IndividualA adjustment is however provided for by fixing to the.`

jack screws hand wheels 219 which will euable either screw to be turned individually to feed it past its worm wheel. Y .Y

The slow wheel is fed' towards or fromthe 55 work by a shaft 220 having a geared con- .ing preferablyincluding changespeed nrec'h-y nection gwith fthe carriage 52 fas indicated iin part at222. The shaftiha'sanoperatingfhand wheel 224 for quick rotation. A hand lever V1226 :is vrockable between spaced lim'it stops 228 land carries a Jpawl 280 engaging yratchet???o teeth on vlthe hand wheel to efl'ecta slow feed. The :fast wheel l'carriage 14 is fed in a similar way, 'the operating wheel beingindicated at 282. The .numeral .234 indicates a controlling 'slow wheelis led down around a drive lp'ulley 242 and the drive pulleys receive power vfrom. any suitable power transmitting f e'ar-` anism. A 35 In setting up, the arms l1 46{are-swim'g down to horizontal position and the rod 142, with a dummy or master workpieee'sleeved' upon it, is held by the taper centers Ain 'the true reference axis of the machine which is 'theigf) -line traversed 'by the centers of :all workpieces. This establishes the position the product piece will occupy at its finished diameter. The work guides and the slow wheel are then moved intocontact with the piece. "93 Upon removing the centering rodf142 land swinging up the arms 146, 'the machine 'is ready for grinding, the Vgrinding wheel being fed in as required' to remove the desired amount of stock. Preferably the work-pieces G0 are fed in a stream by 'suitable mecha? nism through the work :guides 'until the wheels are reached. The 'slow wheel, being tilted, then controls the endwis'e feeding fand rotation of the work. In `-any tilted .posi- 35 tion, the slow .wheel can be dressed and the contour produced is such as to main-tain 1a line contactwith the work-pieces.

This application is a division of my "copending application Serial Number 87,940.y 'f3-10 1.- Ina'centerless grinding machine, a fast wheel, `a slow wheel. a work support, a locating rod extending between the wheels, and means for temporarily supporting the rod `in-115 la `definite and established axis of reference between the wheels; substantially a's described.

2. In a centerlessgrinding machine, a fast wheel, a slow wheel. a work support, a locat--ZO ingrod .extending between the wheels. and aligned centering members for temporarily supporting the rod' in a definite and established axis of reference on vthe machine; substantially as described.

3. In a'centerlessgrinding machine, a fast wheel,.a slow'wheel, a work support, a lo'c'ating rod extending between the wheels, 'centering members for supporting the rod in a definite and established aXis .of reference onf-333 tlie machine and means for moving one of the centering members; Substantially as de- 4. In a centerless grinding machine, a `fast wheel, a slow wheel, awork support, a locating red extending between the wheels, taper centers for supporting thefrodin a deiinite and established axisV ot reference Von Vthe mai chine,pand supporting arms for swinging the taper centers into and out of operative position; substantially as described.

. Y 5. In a centerless grinding machine, arfast wheel,.a slow wheel,`a work support, a locate ing rod extending between the wheels, taper centers for supporting the rod vin a definite and established axis of referenceon the-ina- "chine, supporting arms for swinging the taper centers into and out-of operative position, and meansfor securingsaid arms in established axis of referencev on the machine,

supporting arms for swinging thetaper centers into and out of operative position, and

means formoving one of the taper centers inv Vthe direction of its axis; substantially as described.

7. In a centerlessgrinding machine, a fast wheel', a slow wheel, an upper work guide, a

lower work guide, a locating rod extending between the wheels and between the work guides, and means for supporting the rod in a definite and established axis on the machine; substantially yas described.

8.v In a'centerlessgrinding machine, a fast lwheel,'-avslowwheel, workgindingrmeans, a

locating rod extending between the wheels, means Jfor supporting the rod in a deiinite and established reference axis on the machine,

and a reference or master work-piece sleeved on the rod;.s'ubstantially as described. Y

9. In a centerless grinding machine, a: fast wheel, a slow wheel, a work guide, means'for supporting a reference or masterwork-piece on an. axis extending between the wheels, and

means for moving the work guide and slow scribed.

' p '10. The method' offsetting up kcenterless grinding machines having a fast wheel, a

slow wheel, and work supporting means which consists in supporting a reference or'master work-piece in a deiiniteand established axis vee VVextending between the wheels, moving thework supporting meansand' slow wheel-up to the supported'piece, and removing` the piece; substantially as described.

11'. 'In a centerless grinding machine, `a

. frame, al grinding wheel'rotatable at a grinding speed, a control wheel rotatable, at arelatively slowerspeed to controlthe rotation of ing anunvarying reference axis on the machine frame, and means for locating the axis of dummy workpieces of dierent 2diameters selectively 'in said axis of reference whereby the external surfaces of any of such selected pieces will locate said control wheel for external contact with product pieces of corresponding diameters when their axes are insaid axisof reference; substantially as described. I

12. In a centerlessgrinding machine, a frame, a grinding wheel rotatably-at a-grinding speed, a control wheel rotatable at a relatively slower speed to control the rotation of .work-pieces, meansffor deiinitely establishing an' unvarying reference axis on the inachine frame work-guiding means'betweenthe wheels, and means for locatingY the work-r guiding means with respect to said axis of reference to produce the same location for the axes of work-pieces of different diametersselective-ly; substantially as described.

13. In a centerless grinding machine, a

frame, a grinding wheel rotatable at a grinding speed, a control wheel rotatable at a relatively slower speed to control the rotation of work-pieces, means for causing axial feed movement of the work-pieces between the wheels,l means for definitely establishing yan lunvarying axis on the `machine-frame, workguiding means between the wheels, and means for adjusting the Vwork-guidingmeans and the control wheel with respect to said axis of reference to produce thesaine path of travel for axes of work-piecesof diterent diameters selectively; substantially as described.'

14. In a centerless grinding machine, a

ltrame, a grinding wheel rotatable at a grind- 105 ing speed, a control wheel rotatable at a relatively slower speed tocontrol the rotationof a work-pieee,awork support, and centering tmeans mounted on the frame :tor establish-fY ingthe axis around whichY thework-piece is "to be rotated during the grinding action; ksubstantially as described. l

15. In a centerless grinding machine, a

Vframe, a grinding wheel rotatable at a grind- Y wheelup tothe supported piece to establish f the finished size position: of the correspond- .ingproduct work-piece; substantially as deing speed, acontrol'wheel rotatable at relativelyslower vspeedy to control the rotation of a work-piece, a 'work supporta-nd taper centers aligned with one Vanother to establish` the axis of Vrotation of the work-piece the -wheels,fand means for adjusting saidA support 4to p'eripherally engage and support .work-pieces, means for definitely establish- Y GIF a work-piece for rotation on its established axis; substantially as described.

In a centerless grinding machine, a frame, a grinding wheel and a control wheel spaced to form a work-receiving throat between them, a pair of centering members aligned with the throat for establishing the axis around which a work-piece is to be ground, a work support carried by the machine frame and projecting between the wheels, and means for adjusting said support to peripherally engage and support a workpiece after its axis is established within the throat, one of said centering members being movable endwise towards or from the other; substantially as described.

18. In a centerless grinding machine, a frame, a grinding wheel and a control wheel spaced to form a workreceiving throat between them, a pair of centering members aligned with the throat for establishing the axis around which a work-piece is to be ground, a work support carried by the machine frame and projecting between the wheels, and means for adjusting said support to peripherally engage and support a workpiece after its axis is established within the throat, and at least one of the centering members beingmovable laterally with respect to said axis, to a position out of line with a located work-piece; substantially as described.

19. In a centerless grinding machine, a frame, a grinding wheel and a control Wheel opposed to one another to form a grinding throat between them, centering members carried by the frame, the wheels being adjustable with respect to each other and to the centering members, a work support between the wheels, and means for adjusting the work support towards or from the grinding throat and transversely with respect to the direction of adjustment of the wheels; substantially as described.

20. In a centerless grinding machine, a frame, a grinding wheel and a control wheel opposed to one another to form a grinding throat between them, work centering members carried by the frame at the ends of the throat and establishing a line of reference, a work support projecting into the throat, and means for adjusting the worl; support and the wheels towards or from the line established by the centering members; substantially as described.

21. In a centerless grinding machine, a frame, a grinding wheel and a control wheel opposed to one another to form a grinding throat between them, a work support projecting into the throat, centering members at each end of the throat and in alignment therewith for establishing the axis of a workpiece to be ground, means for adjustingthe distance between said members, and means for moving at least one of said members into and out of alignment with the throat; substantially as described.

22. In a grinding machine, a frame, a grinding wheel, mechanism comprising a pair of centers for determining the axis of rotation of a work-piece to be ground, means lperipherally supporting the work-piece for rotation while it is being ground, and a member frictionally engaging the work-piece for controlling the rotation thereof; substantially as described.

23. In a grinding machine, a frame, a grinding wheel, a work locating device carried by the frame for determining the axis of rotation of a work-piece to be ground, a work support peripherally supporting the work-piece while it is being ground, and a member frictionally engaging the work `for controlling the rotation thereof; substantial ly as described.

In testimony whereof I hereunto aiix my signature.

WILLIAM H. CHAPMAN.

Cil 

